1. Field of the Invention
This invention relates to the storage, transportation, and supply of propellants in space. More specifically, the invention is a reusable space module that can warehouse, transport, and supply high-thrust propellant(s) needed for time critical space travel and low-thrust propellant(s) usable for non-time critical space travel.
2. Description of the Related Art
Many engineering problems must be solved in order to provide safe, affordable, and efficient in-space transportation of both personnel and equipment. These challenges directly impact the commercialization of space. In particular, cost is the single largest obstacle. One method of reducing costs is to develop reusable transportation systems for both Earth-to-orbit systems and in-space systems. Without reusable systems, sustained exploration or large-scale development beyond Low Earth Orbit (LEO) using in-space transportation systems will not be economically feasible.
Significant challenges must be overcome for in-space transportation to become a reality. For example, reusable in-space transportation systems that are affordable must provide good fuel efficiency, be capable of mass production, and be compatible across a broad spectrum of applications. Another significant challenge involves how to minimize the in-space travel time for manned missions. The risk associated with human missions can be significantly reduced by decreasing the time that the crew is in transit.
Currently, the primary propulsion method for manned and unmanned missions utilizes chemical propulsion systems. This trend is expected to continue for the foreseeable future. While nuclear thermal propulsion systems show promise as part of a highly efficient transportation system of the future, the major drawback of a nuclear thermal propulsion system is the inherent public concerns that accompany the use of these systems near the Earth. The chemical propulsion system provides a reasonably high thrust thereby making it a logical choice for time critical space travel. However, one significant drawback to chemical systems is the relatively low specific impulse of this form of propulsion. That is, chemical propulsion systems require large propellant quantities to provide the velocity changes needed to complete a mission. The need for a large amount of propellant translates into a larger, heavier space vehicle which, by itself, exacerbates the need for even more propellant. As a result, chemical propellant-based space vehicles are large and expensive.
In accordance with the present invention, a space module has an outer structure designed for traveling in space. At least one docking mechanism is coupled to an end of the outer structure for facilitating a docking operation therewith in space. A first storage system mounted within the outer structure stores a first propellant that burns as a result of a chemical reaction therein. A second storage system mounted within the outer structure stores a second propellant that burns as a result of electrical energy being added thereto. A bi-directional transfer interface is coupled to each of the first and second storage systems to transfer the first and second propellants into and out thereof.
The space module can be part of a propellant supply architecture that is used for in-space transportation. In this architecture, at least two of the space modules are transported to an orbit in space. A first of the space modules is coupled to a first space vehicle via its docking mechanism. The first space vehicle travels to a location in space using the first propellant (e.g., high thrust propellant when the first space vehicle is a manned vehicle) to generate thrust. A second of the space modules is coupled to a second space vehicle via its docking mechanism. The second space vehicle travels to the same location in space as the first space vehicle, but uses the second propellant (e.g., low thrust propellant when the second space vehicle is an unmanned vehicle) to generate thrust. When it is time for the first (manned) space vehicle to return, the first and second space vehicles swap space modules thereby providing i) a full supply of first propellant for the first space vehicle""s return trip, and ii) a full supply of second propellant for the second space vehicle""s return trip.